1. Field of the Invention
The present invention relates to a fastening element for hard constructional components such as concrete, masonry and the like and including a cylindrical base body having a first end with a bottom section, a second end remote from the first end, inwardly located engagement means for the setting bit and a receptacle opening toward the second end, adjoining the engagement means in a direction toward the second end, and provided with load application means, with the base body being provided with a self-tapping thread, at least regionwise, on its outer surface.
2. Description of the Prior Art
Fastening elements of the type described above are used for attachment of objects to the hard constructional components such as concrete, masonry, and the like. A fastening element is screwed in a preliminary formed borehole with a suitable setting bit, with the self-tapping thread forming a complementary thread in the constructional component or in the borehole wall. The fastening elements is anchored in the constructional component by the undercut formed by the complementary thread. The load application means, which is provided in the receptacle, is formed, e.g., as an inner thread into which an attachment element, such as e.g., a threaded rod or a screw is screwed in to form an attachment. Instead of the inner thread, a bayonet joint can be used.
European Publication EP 1 536 149 A2 discloses a fastening element of a type described above. The known fastening element has a cylindrical base body having a first, facing in the setting direction, end with a bottom section and a second and remote from the first end. On the outer surface of the base body, a self-tapping thread is provided. The base body has inwardly located, engagement means for the setting bit and a receptacle opening to the second end and adjoining, in the direction toward the second end, the engagement means. The receptacle is provided with an inner thread that forms load application means. In the end region of the first end, the engagement means is arranged at the same axial height of the base body as the thread runout of the self-tapping screw.
The drawback of the known fastening element consists in that formation of the engagement means at the bottom of the receptacle is connected with increased manufacturing costs, being costs-intensive. Further, with such fastening element, manufacturing possibilities are limited. Actually, at a mass production, for which such fastening elements are suited, an economical manufacturing is an important competitive advantage.
U.S. Pat. No. 5,630,688 discloses a self-tapping sleeve that is somewhat different from the subject fastening element. The self-tapping sleeve of U.S. Pat. No. 5,630,688 is designed for suspendable plaster ceilings for suspended lighting fixtures and includes a cylindrical base body having a first, facing in the setting direction of the sleeve, end and a second end remote from the first. On the outer surface of the base body, at the first end, there are provided two cutting elements which form, upon setting of the sleeve, an opening for the sleeve in the plaster ceiling. Between the first and second ends of the base body, there is provided engagement means for the setting tool and which simultaneously serves as a through-opening. The base body also has a receptacle opening toward the second end and adjoining the engagement means in the setting direction.
The drawback of the self-tapping sleeve of the above discussed U.S. patent consists in that it is unsuitable for use in hard components such as concrete, masonry and the like as no self-drilling fastening element can be used for such hard components. Nor can the above-described sleeve be used as a fastening element insertable in a preliminary formed borehole. It would have unnecessary cutters at the first end and would not have load application means.
Accordingly, an object of the present invention is to provide a fastening element for hard constructional components and that can be produced simply and, therefore, economically.